From: "Michael E. Mann" To: Tom Crowley Subject: Re: not so fast Date: Tue, 02 Jan 2007 11:18:45 -0500 Reply-to: mann@psu.edu Cc: "raymond s. bradley" , rahmstorf@ozean-klima.de, Eric Steig , gschmidt@giss.nasa.gov, rasmus.benestad@physics.org, garidel@marine.rutgers.edu, Caspar Ammann , William Connelley , d-archer@uchicago.edu, rtp1@geosci.uchicago.edu, p.jones@uea.ac.uk for those who are interested, there is a paper by Goosse et al (I'm a co-author) explaining why parts of Europe such as central england would have experienced warmer summer conditions relative to present than other regions, related to early land-use change: Goosse, H., Arzel, O., Luterbacher, J., Mann, M.E., Renssen, H., Riedwyl, N., Timmermann, A., Xoplaki, E., Wanner, H., [1]The origin of the European "Medieval Warm Period", Climate of the Past, 2, 99-113, 2006. paper available as pdf here: [2]http://www.meteo.psu.edu/~mann/shared/articles/Goosseetal-CP06.pdf meanwhile, winter warmth could have been due to a strong AO/NAO pattern associated with decreased volcanism and high solar, as discussed in the various Shindell et al paper. this simply underscores the point that we all often make, that one needs to take into account regional factors when interpreting regional records. This is especially relevant to the extrapolation of a long record from England to the entire NH (which appears to have been tacitly done by Jack Eddy?), mike Tom Crowley wrote: we still don't have an adequat explanation as to how Jack "cooked up" that figure - I do not believe it was purely out of thin air - look at the attached - which I used in the Crowley-Lowery composite just because it was "out there" - I made no claim that it was the record of record, but just that it had been used beforer. the Lamb ref. is his book dated 1966. I will have to dig up the page ref later. Dansgaard et al. 1975 Nature paper on Norsemen...etc used that figure when comparing what must have been their Camp Century record - have to check that too - where the main point of that paper was that the timing of Medieval warmth was different in Greenlandn and England! 25 years later my provocation for writing the CL paper came from a strong statement on the MWP by Claus Hammer that the canonical idea of the MWP being warming than the present was correct and that the 1999 Mann et al was wrong. he kept going on like that I reminded him that he was a co-author on the 1975 paper! that is also what motivated to do my "bonehead" sampling of whatever was out there just to see what happened when you added them all together - the amazing result was that it looked pretty much like Mann et al. ther rest is history -- much ignored and forgotten. I might also pointn out that in a 1996 Consequences article I wrote - and that Fred Singer loves to cite -- Jack (who was the editor of the journal) basically shoehorned me into re-reproducing that figure even though I didn't like it - there was not an alternative. in the figure caption it has a similar one to Zielinski except that it states "compiled by R.S. Bradley and J.A. Eddy based on J.T. Houghton....so that puts a further twist on this because it point to Houghton not Bradley/Eddy as the source. Jack must have written that part of the figure caption because I don't think I knew those details. but we still don't know where the details of the figure came from - the MWP is clearly more schematic than the LIA (actually the detailsl about timing of the samll wiggles in the LIA are pretty good) - maybe there was a meshing of the Greenland and the England records to do the MWP part - note that the English part gets cooler. they may also have thrown in the old LaMarche record - which I also have. maybe I can schlep something together using only those old three records. tom Michael E. Mann wrote: Ray, happy holidays and thanks for the (quite fascinating) background on this. It would be good material for a Realclimate article. would be even better if someone could get Chris on record confirming that this is indeed the history of this graphic... mike raymond s. bradley wrote: I believe this graph originated in a (literally) grey piece of literature that Jack Eddy used to publish called "Earth Quest". It was designed for, and distributed to, high school teachers. In one issue, he had a fold-out that showed different timelines, Cenozoic, Quaternary, last 100ka, Holocene, last millennium, last century etc. The idea was to give non-specialists a perspective on the earth's climate history. I think this idea evolved from the old NRC publication edited by L. Gates, then further elaborated on by Tom Webb in the book I edited for UCAR, Global Changes of the Past. (This was an outcome of the wonderful Snowmass meeting Jack master-minded around 1990). I may have inadvertently had a hand in this millennium graph! I recall getting a fax from Jack with a hand-drawn graph, that he asked me to review. Where he got his version from, I don't know. I think I scribbled out part of the line and amended it in some way, but have no recollection of exactly what I did to it. And whether he edited it further, I don't know. But as it was purely schematic (& appears to go through ~1950) perhaps it's not so bad. I note, however, that in the more colourful version of the much embellished graph that Stefan circulated ([3] http://www.politicallyincorrect.de/2006/11/klimakatastrophe_was_ist_wirkl_1.html the end-point has been changed to 2000, which puts quite a different spin on things. They also seem to have fabricated a scale for the purported temperature changes. In any case, the graph has no objective basis whatsoever; it is purely a "visual guess" at what happened, like something we might sketch on a napkin at a party for some overly persistent inquisitor..... (so make sure you don't leave such things on the table...). What made the last millennium graph famous (notorious!) was that Chris Folland must have seen it and reproduced it in the 1995 IPCC chapter he was editing. I don't think he gave a citation and it thus appeared to have the imprimatur of the IPCC. Having submitted a great deal of text for that chapter, I remember being really pissed off that Chris essentially ignored all the input, and wrote his own version of the paleoclimate record in that volume. There are other examples of how Jack Eddy's grey literature publication was misused. In a paper in Science by Zielinski et al. (1994) [v.264, p.448-452]--attached-- they reproduced [in Figure 1c] a similarly schematic version of Holocene temperatures giving the following citation, "Taken from J. A. Eddy and R. S. Bradley, Earth-quest 5 (insert) (1991), as modified from J. T. Houghton, G. J. Jenkins, J. J. Ephraums, Climate Change, The IPCC Scientific Assessment (Cambridge Univ. Press, Cambridge, 1990)." But I had nothing to do with that one! So, that's how a crude fax from Jack Eddy became the definitive IPCC record on the last millennium! Happy New Year to everyone Ray Raymond S. Bradley Director, Climate System Research Center* Department of Geosciences, University of Massachusetts Morrill Science Center 611 North Pleasant Street AMHERST, MA 01003-9297 Tel: 413-545-2120 Fax: 413-545-1200 *Climate System Research Center: 413-545-0659 <[4] http://www.paleoclimate.org> Paleoclimatology Book Web Site: [5]http://www.geo.umass.edu/climate/paleo/html Publications (download .pdf files): [6]http://www.geo.umass.edu/faculty/bradley/bradleypub.html -- Michael E. Mann Associate Professor Director, Earth System Science Center (ESSC) Department of Meteorology Phone: (814) 863-4075 503 Walker Building FAX: (814) 865-3663 The Pennsylvania State University email: [7]mann@psu.edu University Park, PA 16802-5013 [8]http://www.met.psu.edu/dept/faculty/mann.htm -- Michael E. Mann Associate Professor Director, Earth System Science Center (ESSC) Department of Meteorology Phone: (814) 863-4075 503 Walker Building FAX: (814) 865-3663 The Pennsylvania State University email: [9]mann@psu.edu University Park, PA 16802-5013 [10]http://www.met.psu.edu/dept/faculty/mann.htm References 1. file://localhost/tmp/Goosseetal-CP06.pdf 2. http://www.meteo.psu.edu/~mann/shared/articles/Goosseetal-CP06.pdf 3. http://www.politicallyincorrect.de/2006/11/klimakatastrophe_was_ist_wirkl_1.html 4. http://www.paleoclimate.org/ 5. http://www.geo.umass.edu/climate/paleo/html 6. http://www.geo.umass.edu/faculty/bradley/bradleypub.html 7. mailto:mann@psu.edu 8. http://www.met.psu.edu/dept/faculty/mann.htm 9. mailto:mann@psu.edu 10. http://www.met.psu.edu/dept/faculty/mann.htm